A crosslinked polyurethane (PU) based on 4,4'-dlphenyl methane diisocyanate (MDI), poly(propylene glycol) (PPG), and trimethylol propane (TMP) was prepared in order to conduct the developement of PU/PU composites by reclaiming polyurethane wastes. The crosslinked polyurethane was ground into small particles to make PU( particle)/PU(matrix) composites. Physical properties such as density and hardness of the composites were almost the same as those of standard polyurethane. However, mechanical properties such as impact strength, tensile strength, and elongation at break were deteriorated in the case of composites. Even though the compatibility and the hydrogen bonding at the interface were not affected by the introduction of polyurethane particles, those particles made the formation of hard phase difficult, which resulted in the reduction of mechanical strengths. This effect was more signification in the case of the increase of particle content than the increase of particle size. In addition, the increase of the wetting or swelling time improved impact strength but decreased tensile strength. This may be due to the fact that under the relatively slow tensile stress applied, polyol chains which interpenetrated into particles were disentangled without contributing to the tensile strength.